Justin Bieber flashes his Abs at the Mayweather Vs. Pacquiao pre-party

The 21-year-old singer lifted up his shirt to display his amazing abs at Rehab pool at The Hard Rock Hotel and Casino on Saturday afternoon May 2 2015 in Las Vegas.

Justin Bieber who is a friend with Mayweather was hosting a pool party before the Floyd Mayweather vs. Manny Pacquiao Fight tonight.

“heading to vegas to host @RehabLV tomorrow for #FightWeekend. who’s coming?” Justin tweeted the day before.